Re: Routing table drops packets via ppp0

From: Mark Devin (mdevin_at_ozemail.com.au)
Date: 10/22/03

  • Next message: David Lloyd: "Re: update in sid has killed gnome-terminal" 
    Date: Wed, 22 Oct 2003 15:06:51 +1000
To: Debian User <debian-user@lists.debian.org>

    Greg Folkert wrote:
    > On Tue, 2003-10-21 at 03:39, Mark Devin wrote:
    >
    >>I am having some trouble getting routing to work properly on a box with
    >>three network connections. One, eth0, is connected to a router and is
    >>the default gateway. Another, ppp0 (eth1 - ADSL) is connected to a
    >>private network on the 192.168.17.0/24 address range. The third is a
    >>standard LAN (eth2) on 192.168.2.0/24.
    >>
    >> From the debian box, I can ping other machines connected via the ADSL
    >>modem via ppp0. I can also ping machines on the internet via eth0 from
    >>this box. In addition, any machine on the Office LAN can connect to
    >>machines on the internet.
    >>
    >>However, if a machine on the office LAN tries to connect to a machine on
    >>the 192.168.17.0/24 network, the packets disappear somewhere in the
    >>debian box. I can see the packets coming in with tcpdump but then they
    >>disappear. The debian box does not try to route them at all.
    >>
    >>Note that I have switched off all firewalling and switched ip_forwarding
    >>on in the kernel.
    >>
    >>The problem is related to the ADSL - ppp0 interface. The routing rules
    >>look OK. I can ping from the debian box via ppp0 to hosts on the
    >>connected network. However, if I ping from the office LAN, the packets
    >>do get to the debian box OK, but it doesn't route them out ppp0. It
    >>just seems to drop them. There is nothing in the logs to indicate any
    >>errors. The packets just disappear.
    >>
    >>The setup looks like this:
    >>
    >> Internet
    >> |
    >> x.x.47.224/27 Router x.x.47.225
    >> |
    >> eth0| x.x.47.226
    >> |
    >>#------------# (eth1 -ppp0 ADSL)
    >># Debian Box #--192.168.17.2-->x.x.16.78-->192.168.17.0/24
    >>#------------#
    >> |
    >> eth2| 192.168.2.1
    >> |
    >> |
    >> Office LAN (192.168.2.0/24)
    >>
    >>The routing table looks like:
    >># route -n
    >>Destination Gateway Genmask Flag Met Ref Use Iface
    >>x.x.16.78 0.0.0.0 255.255.255.255 UH 0 0 0 ppp0
    >>x.x.243.224 0.0.0.0 255.255.255.224 U 0 0 0 eth0
    >>192.168.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2
    >>192.168.17.0 x.x.16.78 255.255.255.0 UG 0 0 0 ppp0
    >>0.0.0.0 x.x.243.225 0.0.0.0 UG 0 0 0 eth0
    >
    >
    > Silly question:
    >
    > Are you running a routing daemon?
    >
    No. Are you talking about the ARP daemon support in the kernel?

    I have compiled my own kernel for this box and it doesn't have the ARP
    daemon support.

    What I can't understand is that the box will route packets correctly
    when they are generated on the box itself. I have ip_forwarding
    switched on and yet it seems to drop packets somewhere when it should be
    routing them. I can see packets coming in but they don't go out.

    Is there anyway that I can log what is happening in the routing process?

    Regards.
    Mark. 

    -- 
To UNSUBSCRIBE, email to debian-user-request@lists.debian.org 
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org
  • Next message: David Lloyd: "Re: update in sid has killed gnome-terminal"

    Relevant Pages